Cramer says anyone who sells big tech stocks in pre-trading is “either a machine or an idiot.”

CNBC’s Jim Cramer on Monday warned investors that thin-trading stocks early in the morning before trading is not a sound strategy.

“The sale of these Nasdaq names between 4 a.m. and 4:30 a.m. is terrifying.” Cramer said on “Squawk on the Street”. “I always think it’s a machine or an idiot, because who wants to sell there without real buyers.”

Nasdaq-linked futures, which were down 2.6% last week, did not participate in Monday’s rebound, which drove many non-tech stocks higher before regular Wall Street trading hours at 9:30 a.m. ET started. After the opening, the Nasdaq rose but fell short of the strong rallies in the Dow Jones Industrial Average and the S&P 500.

The Nasdaq was about 6% off its last record high on November 19th on Friday. The Dow was about 5% off its November 8th high. The S&P 500 was nearly 3.7% off its November 18th record high.

Cramer said many of the big tech stocks that make up the Nasdaq are in a bear market, defined as 20% or more away from recent highs.

“Swapping the ribbon is a real mistake here. It could reverse itself in a nanosecond,” Cramer said earlier in CNBC’s “Squawk Box,” pointing out that selling on Nasdaq could turn into buy in this volatile market environment .

Cramer has never shied away from criticizing “pajama dealers,” as he calls them. In some examples, the Mad Money host blew them up in 2017 and 2019.

Join Now for the CNBC Investing Club to follow Jim Cramer’s every move in the market.